Collagen is a structural protein found in the connective tissues of terrestrial and marine animals. Its diverse functional attributes span its applications in several industries, including food, supplements, cosmetics, and pharmaceuticals. Typically derived from mammalian sources, collagen and its derivatives, including gelatin and collagen peptides, are essential for the food and supplement industries. Recently, marine collagen has emerged as a viable mammalian collagen alternative due to its unique functionality and sustainability. Marine vertebrates and invertebrates are reliable sources of marine collagen. Some marine organisms are promising sustainable sources of collagen for nutritional applications. Recent research highlights significant advances in marine collagen extraction, processing, and novel applications. Hence, recent interest has propelled research in identifying novel collagen sources and advancing technologies to produce marine collagen-based products. Considering the recent scientific interest in marine collagen, this review provides an overview of recent progress in marine collagen production, including novel sources, innovative processing technologies, nutritional and functional properties, safety and quality control, current challenges, and future research directions. The review highlights certain challenges, including unpleasant odor, flavor, color, insufficient supply, and inconsistent quality of marine collagen. Future research should focus on increasing the collagen extraction yield, improving the smell and flavor, and developing novel delivery systems to increase bioavailability and functionality.